Table 1

Summary characteristics of the included studies

Study characteristics	n	%	Physician characteristics	n	%	Exposures, interventions and outcomes	n	%
Study design			Gender			Exposures (observational)*	45	96
Cross-sectional	34	72	Reported†	38	81	Fatigue related	15	32
Cohort	6	13	>50% male	30	79	Sleep related	37	79
Before-after	3	6	Age			Overnight or extended shifts	18	38
RCT	2	4	Reported†	38	81	Interventions (experimental)	2	4
Time series	1	2	Range (years)	20 to >70		Outcomes
Non-comparative	1	2	Specialty area ‡			Physician health and well-being	28	60
Region and country			Surgeons	13	28	Work and life satisfaction	9	19
North America	20	43	Anesthesiologists	10	21	Burn-out	7	15
USA	15	32	Generalists	7	15	Stress	8	17
Canada	4	9	ED or ICU physicians	3	6	Mental health and well-being	7	15
Canada, USA and Mexico	1	2	Oncologists	2	4	Other health-related outcomes	5	11
Europe	16	34	Obstetrician-gynaecologists	1	2	Physician performance, risk of error	21	45
France	4	9	Mixed groups	14	30	Psychomotor performance	7	15
Finland	3	6	Work setting §			Work ability and quality of care	5	11
Spain	2	4	Hospitals	37	79	Incidence of medical errors	5	11
Austria	2	4	Private practice	13	28	Surgical efficiency, effectiveness	6	13
Norway	2	4	Primary care centres, outpatient clinics	7	15	Patient outcomes	6	13
Denmark	1	2	Academic practice, training programmes	5	11
Germany	1	2	Other (eg, industry, military)	11	23
Malta	1	2	Not reported	3	6
Japan	4	9	Urban or rural
Australia	2	4	Reported†	16	34
Israel	2	4	Urban	12	75
New Zealand	2	4	Rural	2	13
UK	1	2	Mixed	2	13

*Exposures that have been directly related to an outcome. Some studies included multiple exposures.
↵†Percentages presented using the total number of studies where the outcome was reported as the denominator.
↵‡Anesthesiologists include physician anaesthetists; generalists include primary care physicians, internists and general practitioners; mixed groups refers to studies including more than one physician group or specialty (usually large-scale surveys). In some studies, multiple distinct groups were represented.
↵§As defined by the authors. Values for the settings will exceed 100% because studies may occur in more than one setting.
ED, emergency department; ICU, intensive care unit; RCT, randomised controlled trial.